This invention relates to adjustable chair-type seats, and more particularly to such seats that include provisions for changes in passenger orientation.
A variety of adjustable seats have heretofore been proposed for human occupancy. These have included a variety of seating arrangements that have been configured to the human form, to provide comfort and support, both in the lower portion of the seat which bears the principal vertical load, as well as the back, which provides support for the upper portion of the human form.
Seating construction is particularly important in vehicular transport where not only comfort of the occupant is important but in which safety becomes paramount. Thus, there have been proposed a variety of vehicular seats which include considerations of both comfort and safety. Illustrative of such is the seating arrangement disclosed in U.S. Pat. No. 3,489,459, granted to Earl R. Katin, Sr. et al. on Jan. 13, 1970.
Transportation seats heretofore proposed have generally involved the provision of a stationary lower portion which is affixed to the main supporting surface. (e.g., compartment floor). Attached to and in swivelable association with such lower stationary portion is the upper backrest and support portion. Although such seats have found widespread use, they have presented certain problems, among which are limits on the degree of adjustment without encroaching inordinantly on adjacent space, limits on passenger comfort, and limitations on the food serving trays that typically are associated with such seats.
Although transportation seats generally have included a stationary lower seating portion, there have been limited proposals for rendering the lower seating portion movable with respect to the stationary undercarriage. Such proposals are illustrated by the disclosure of the aforementioned Katin patent. According to that proposal, the lower seat portion is made pivotable about a location near the front thereof, which location also presents a sliding connection to the stationary undercarriage; and a connection from a point forward of the pivot location to a point on the backrest portion above its pivotable connection to the stationary undercarriage results in a rearward and downward movement of the rear of the lower seating portion when the backrest portion is reclined. However, the back continues to swivel about a stationary point, thus limiting the extent of inclination without unduly encroaching on the space of the passenger immediately behind. Accordingly, there has continued to be a need for further improvements in such seats to provide for coordinated movement of both the lower and upper portions of the seat both with respect to the undercarriage and with respect to each other.